Struct Environment

pub struct Environment { /* private fields */ }

An Environment is a hashmap in which SAP variables and functions are stored. It also contains an optional reference to the outer environment. This creates a tree of environments, where each environment can lookup all the variables and functions of it’s parent enviornment.

Implementations

impl Environment

pub fn new() -> Self

pub fn new_enclosed_environment(outer: &EnvRef) -> Self

Creates a new child Environment to the given outer environment.

Equivalent to:

let mut env = Environment::new();
env.outer = Some(Rc::clone(outer));

pub fn lookup(&self, name: &str) -> Option<Rc<Value>>

Looks up the given name in the current environment and all parent environments.

If the name is found, the function returns a reference to the Value associated with the name. If the name is not found, the function returns None.

pub fn store(&mut self, name: String, value: Rc<Value>)

Stores the given name and value in the current environment.

Trait Implementations

impl Debug for Environment

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for Environment

Implements the Display trait for Environment. This allows an Environment to be printed in a human-readable format.

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for Environment

fn eq(&self, other: &Environment) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for Environment